Lead-in wire for electric lamps.



No. 740,260. I PATENTBD SEPT. 29, 1903.

J. G. BNTR'IKBN 6v W.' S. EVERBTT.'

LEAD-IN WERE FOR ELEGTRIG LAMPS. AB-B'LLQATION FILED me... 2.1 1903.

N0 MODEL.

UNITED STATES Patented September 29, 1903.

'i PATENT OFFICE.

JOHN O. ENTRIKEN AND I/VILLIAM S. EVERETT, OF MALVERN, PEN N SYLVA- NIA, ASSIGNORS OF ONE-FOURTH TO SHELDON M. CUSTER, OF WAYNE,

PENNSYLVANIA.

LEAD-IN WlR FOR ELECTRIC LAMPS.

SPECIFICATION forming part of Letters Patent No. 740,260, dated September 29, 1903.

Application filed August 2l, 1903. Serial N0.170,358. (No model.)

To all whom it may concern:

Be it known that we, JOHN C. ENTRIKEN and WILLIAM S. EVERETT, citizens of the United States, and residents of Malvern, county of Chester, State of Pennsylvania, have invented certain new and useful Improvements in Lead-In Wires for Elect-ric Lamps, of which the following is a specification.

Our invention relates to electric lamps,

ro such as incandescent electriclights, and more especially to certain improvements in connection with the lead-in wires of the lamp.

The object of our invention is to provide an eicient and economical means of attachx5 ing a platinum or other coated lead-in wire to the stemof such a lamp, so designed as to eifectually prevent any leakage of air into the bulb after the vacuum has been established.

Attempts have been made to utilize platinum-coated lead-in wires inV incandescent electric lamps because of the material reduction in cost which would result from the use of a platinum-coated wire' instead of the 2 5 solid platinum wire now universally employed; but such attempts have proved failures by reason of the fact that it has not been possible prior to our invention to prevent leakage of air from the'stem by the embedded 3o lead-in wires into the bulb, thereby destroying the vacuum. YIt has been commonly supposed that this leakage occurred between the outer surface of the coated wire and the mass of glass of the stem in which vthe said wire has been embedded; but we have discovered that this leakage occurred between the metallic core and the platinum coating. By our invention we are enabled to prevent the said leakage, and thereby to successfully apply a 4o coated lead-in wire to electric lamps.

Our invention consists, broadly, in the employment, in connection with an electric lamp, of a coated lead-in wire having the end otherwise exposed to the air or to which air had access sealed against such access of air between the coating and the core of the wire, and, further, in such a coated lead-in wire having such end glass sealed against access of air, and, further, in such a coated lead-in 5o wire having such end bent and embedded in the glass of the stem, whereby it is sealed against access of air and'furnishes a ready means of connection with the conductingwire, and, finally, in the novel construction and details thereof, as hereinafter described with reference to the accompanying drawings, and more particularly pointed out in the claims.

In the accompanying drawings, Figure lis a side elevation of an ordinary electric lamp, showing our invention applied thereto. Fig. 2 is an enlarged sectional detail showing the preferred form of sealing the end of the coated lead-in wire. Fig. 3 is a detail view of a modification, and Fig. 4 is a similar view of a further modification.

Referring to the drawings, in which the same reference characters relate to the same parts in all the views, l represents an electric-lamp bulb provided with the usual base 2, from which extends the usual glass stem 3, through which stem extend conductorwires 4, having their ends embedded in the flattened end portion 5 of the tubular stem and in conducting contact with the lead-in wires 6, to which the filament 7 is attached in the usual manner.

According to our invention the lead-in wires 6 are preferably composed of an inner core 8 of a metallic conducting-wire of higher conducting power than platinum-such, for example, as iron, coated with a thin coating 9, preferably of platinuma conducting contact between said lead-in wires and the conducting-wires It being eected by bending the ends of said conductingwires around the lead-in wires and forcing the same into permanent contact during the operation of closing the lower end of the stem 3 by subjecting the same to pressure, as is well understood by those skilled in the art, or this contact may be secured in any other convenient way. In order to preven-t access of air from the stem to the bulb around or through the coated lead-in wire, we seal the end 10, which would 95 otherwise be exposed to the air or to which air might otherwise gain access, preferably by bending the same in such manner that when the lower end 5 of the stem is closed the end 10 will be permanently embedded in loe the mass of glass, and thus sealed against access of air, so that it will be impossible for air to penetrate between the core 8 and the coating 9 of said lead-in wire. Thus the passage of airinto the bulb is prevented and the vacuum maintained intact. In this form of tl1einvention the bent ends aiord a simple means of connecting the conducting-wires, the union between the two being eected in the closing of the end of the stem, thus in closing the joint in the mass of pressed glass.

While the preferable form of our invention is that embodied in Figs. l and 2 of the drawings, the same result may be accomplished in a variety of ways; the only requirement being that the end of the coated wire which would otherwise be exposed to the air shall be protected against the access of air. For example, in Fig. 3 we have shown a form in which the end IO of the lead-in'wire is extended through the attened or closed end 5 of the stem, so that it will be exposed to the vacuum in the bulb l and not to the air, or, if desired, the end l0b of the lead-in wire 6 may be extended upwardly through the closed end of the stem into the said stein and provided with a seal 1'1, preferably of glass, so as to eii'ectually close the end ofthe coated leadwire against access of air.

By the use of our invention a large saving of platinum (the metal possessing the properties most suitable for lead-in wires in electric lights for reasons well known to the art) is effected, for only a very thin coating of platinum is necessary to answer the purpose of the present solid platinum wire. i

While our invention is especially adapted to incandescent electric lights, it is to be observed that its utility is not limited in this respect, since it is apparent that it may be applied wherever a coated lead-in wire is used for conveying an electric current into a lamp body or bulb wherein a vacuum must be 'Maceo maintained, and when the term stem is employed in this specification it is intended to include the portion of the device through which the lead-in wires pass to the vacuumbulb, no matter what form that stem may be.

We claim as our invention- 1. In an electric lamp, a coated lead-in wire having its end sealed to prevent access of air between the coating and core of said, wire, substantially as described.

2. In an electric lamp, a coated lead-in wire having its end glass-sealed to prevent access of air between the coating and core of said wire, substantially as described.

3. In an electric lamp, a coated lead-in Wire having a bent end sealed against access of air between the coating and the core of said wire, substantially as described.

4. In an electric lamp, a coated lead-in wire having a bent end embedded in the glass of the stem, thereby preventing access of air between the coating and core of said wire, substantially as described.

5. In an electric lamp, a platinum-coated lead-in wire havingits end protected against access of air between the platinum coating and the core of said wire, substantially as described.

6. In an incandescent electric lamp, a platinum-coated lead-in wire having its end bent to furnish contact for the conductor-wire, and embedded in and inclosed by the glass of the stem, whereby leakage of air into the bulb through said wire is prevented, substantially as described.

In testimony whereof we have signed our names to this specification in the presence of two subscribingwitnesses.

JOHN C. ENTRIKEN. l WILLIAM S. EVERETT. Witnesses:

JOHN I-I. SIGGERS, R. T. FRAZIER. 

